outlook.js

var authContext;
var authToken; // for use with creating an outlookClient later.
authContext = new O365Auth.Context();
authContext.getIdToken("https://outlook.office365.com/")
   .then((function (token) {
       authToken = token;
       // The auth token also carries additional information. For example:    
       userName = token.givenName + " " + token.familyName;
   }).bind(this), function (reason) {
       console.log('Failed to login. Error = ' + reason.message);
   });
   
// Once the authToken has been acquired, create an outlookClient. One place to do this is inside of the
//    ".then" function callback of authContext.getIdToken(...) above.
var outlookClient = new Microsoft.OutlookServices.Client('https://outlook.office365.com/api/v1.0', authToken.getAccessTokenFn('https://outlook.office365.com'));